924Board.org

[JH-Q]

Hello again. This started when my -82 NA engine suddendly stalled while accelerating on a highway ramp six weeks ago. It didn't do anything before stalling, it just went like someone turned the key off. Didn't start again, just cranked with the starter and normal fuel pump noise. Towed it back home and began searching for faults; began by checking the fuel to distributor which was ok and there was enough of flow. Then checking the spark which was weak, replacing distributor cap, plug wires, coil, and ignition control module and checking engine grounding. I got a good spark then, but still no start. Pulled one of the injectors and saw no fuel there. When lifting the air sensor plate by hand and cranking, i got fuel from the injector, but none with cranking alone. I suspected it was a vacuum leak so i checked the hoses, replaced one cracked one and repaired a plastic coupling which was a bit bent so it might have been leaking.

When i had a friend from local Porsche club visiting and checking my problems, i noticed sizzling sound, looked under the car where i thought the sound was coming and saw fuel leaking out from the fuel line front of driver side rear wheel. As it began being too cold outside a few days after that, cleaned the garage and took inside for fuel supply repairs. Drained the tank and looked inside, it was suprisingly clean, as it was repaired by a local Porsche dealer seven years ago. The internal fuel pump was in good condition, so i put it back and checked the other components. External fuel pump and accumulator were badly corroded so i replaced them and hoses betveen them. Finally i replaced the fuel lines and the fuel filter.

Still not starting, i took the air filter off and checked if the sensor beam under the air sensor plate was moving while cranking, and it was. So that indicates the vacuum would be ok? Still not fuel at injector. Today i checked the cold start valve (which was giving fuel), and auxiliary air regulator (which let air through when cold)

Now i have no idea what to do next, i suspect the fuel distributor is broken or jammed by something, but i won't open it unless i really have to. I have heard some horror stories of distributor repairs.
If you have any ideas, please don't hesitate to tell them, i will do the testing and post results. I really miss driving my own Porsche after six weeks and want to get it back on the road soon

[Nobbi]

Hey,

you replaced the fuel-lines before and after the fuel pump? All of them?
I heard about a problem like yours and it turned out that on of the rubber fuel hoses befor the fuel pump was soaking air thru the old rubber material.Its easyier for the fuel-pump to pump air instead of gas,and thats what she was doing......

Nobbi

[JH-Q]

Yes, i changed all the hoses. Old ones didn't look that bad either but the fittings and metal lines were corroded.

[gohim]

I take it that you replaced the "igniter" ignition module on the left front inner fender?

The problem that I had had with my 91 924, Dodge Omni, and VW Fox was a defective breakerless ignition module inside of the distributor. This is a Bosch manufactured part, and the design seems to be prone to failure after 100K miles.

The particular type of module that I am talking about was used on 924s starting in 1980, and used till the 924 was discontinued in all markets after 1985.

Here in the US, the module costs $75-$100, and must be installed by a shop because a hydraulic press is necessary to disassemble the distributor. Because of this, when my module failed, I took it to a Bosch Authorized Shop where the distributor was serviced (checked internal components including the bushings for wear) the module replaced, and the distributor throughly tested (including the advance mechanisms) before I got it back.

[Ozzie]

Check the fuel delivery and spray pattern of the injectors and fuel pump.
Test procedure in the haynes.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[gohim]

If the breaker module in the distributor that I mentioned earlier fails, the fuel pump is not going to run when the key is in the ignition on/engine run position.

[Vince Ponz]

Stalling on the highway and then it starts again after you stop the car??
It happened to me and it was the ignition switch.
_________________
"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

[JH-Q]

Fuel delivery is ok to distributor, and can't check spray pattern as there is no fuel at injectors.

Will be checking the breaker module this weekend, that sounds like it could be a problem.

Stalled on the highway, and no start since then, not even a single piston fire.

[gohim]

When the breaker module inside of the distributor on my car first started to fail, the car was hard to start sometimes, and sometimes when it was running, it would die without warning, but was able to restart almost immediately.

This gradually got worse until one day, after I started the car, and drove about 1/2 mile, the engine died without warning, and would not restart.

I had the car towed back to the house, and took a look at the problem a couple of days later. Discovered that the car had no spark, and traced the problem to the module.

[gohim]

You can bypass the fuel pump delay to force the fuel pump to run continuously. This would allow you to check the spray patterns of the fuel injectors, and verify that the ignition switch, and the fuel pump are good before you concentrate on the ignition distributor and module as the prime suspects.

[JH-Q]

The previous owner already did that bypass modification on the relay, there is a switch under the dash in driver side footwell, and the pump can be turned manually on. External fuel pump is new and orginal Bosch, so that's not an issue. When using the pump, i don't get any fuel at the injectors, might try by lifting the air sensor plate while having the fuel pump on.

[JH-Q]

Today i got fuel at injectors 3 and 4, didn't check the other two. None at air sensor plate down, and more when lifting it and cranking or running the fuel pump. I think i'm still getting spark, but will probably check that again. Could it be timing, and how could it have been changed while driving?
Timing belt skip? The belt is almost new at 1500km on it, and properly tightened. If the timing is incorrect, should i get any pistons to fire, or would it be quiet, only cranking? I don't think it's flooding either, as the injectors don't leak while the air sensor plate is down and fuel pump running.

[Rich H]

My dizzy got stuck at full advance.... didn't help at all...
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

[JH-Q]

I fount the problem, my timing belt had lost ALL of its teeth No idea why, the tensioner bearing was ok when i replaced the belt 1500km ago. Could it be too tight? I tensioned the belt with the 90-degree twist medhod. I have heard it's a little too tight. Or could it be aftermarket replacement wasn't good enough?

[RC]